1. Field of the Invention
The present invention relates in general to a novel ignition system and in particular to a novel ignition system for use with internal combustion engines.
2. Description of the Prior Art
Conventional ignition systems for internal combustion engines have proven themselves to be reliable and adequate for many years. In recent times these systems have been upgraded by means of various electronic switching apparatus. However, even with the addition of the electronic apparatus, the systems remain very similar in operation to the conventional electromechanical systems.
Modern engines are required to meet a multitude of ever tightening standards regarding the quantity and quality of exhaust emissions. In order to meet these requirements, engine manufacturers have resorted to producing engines which operate under very lean air to fuel mixtures and engines which employ stratified charge or tubulant flow technology. Lean burning engines require increased spark duration for proper operation. This is accomplished in the conventional systems by increasing the open circuit spark voltage. However, increasing the voltage results in an increase in the amplitude as well as the duration of the spark current which greatly decreases the life of the spark plugs. In turbulant flow-type systems, the flow of the charge within the individual cylinders of the engine tends to blow out or extinguish the arc occuring within the spark plug prematurely thereby decreasing the duration of the spark which is detrimental to proper ignition.
The present invention is directed to a novel AC ignition system which produces an alternating current and therefore an intermittent spark within the spark plug. In such an AC system, the duration of the ignition can be greatly increased over that of the conventional systems without a corresponding decrease in spark plug life. Also, since the total ignition comprises a plurality of short intermittent sparks, the blow out problems of turbulant flow engines are greatly reduced.
Another problem inherent in conventional designs is that they generally use a common high voltage generator in the form of a single ignition coil for all the spark plugs in the engine. The high voltage from the single coil is then distributed to the various plugs by means of a rotary high voltage switch or distributor and a system of high voltage cables. The distribution and high voltage cables are well known to be frequent sources of problems and thus are the weak links in the conventional system.
The present invention is directed to a novel ignition system which overcomes the difficulties inherent in the conventional systems utilizing a common high voltage generator by providing an essentially independent high voltage generator system for each spark plug in the engine. An individual ignition transformer is provided for each spark plug. In a preferred embodiment, each ignition transformer is built into a novel spark plug cover which thus acts to eliminate the need for high voltage wiring. The distributor of the conventional system is also electronically eliminated.